答复: 答复: 答复: [PATCH] ext4: e2fsprogs: fix inode bitmap num not integer,incompatible for ancient android devices

From: Gaoming (ming, consumer BG)
Date: Thu Jun 28 2018 - 22:06:33 EST


We use usual inode size, it is 256 bytes.

Yes, this commit is in my repository.
But there is a bug in this patch.

Let me show you,
Here is the bug: " return ALIGN(inodes, (info.block_size / info.inode_size));"

In my reproduce,
info.block_size = 1024, (it is legal)
info.inode_size =256,

the code only ALIGN BY 4.

But in real scenario, we should align by 8,( 8 bit per bytes in inode map).

So we got Inodes per group: 1708 , which is illegal.

Like below,

./host/linux-x86/bin/make_ext4fs -s -l 20M -b 1024 gaoming.img
Creating filesystem with parameters:
Size: 20971520
Block size: 1024
Blocks per group: 8192
Inodes per group: 1708
Inode size: 256
Journal blocks: 1024
Label:
Blocks: 20480
Block groups: 3
Reserved block group size: 95
Created filesystem with 11/5124 inodes and 2509/20480 blocks

This bug exists very very long time till now.


Regards,
Ming

-----邮件原件-----
发件人: Theodore Y. Ts'o [mailto:tytso@xxxxxxx]
发送时间: 2018年6月28日 23:30
收件人: Gaoming (ming, consumer BG)
抄送: linux-ext4@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Liqingchao (sorp); Shenchen (harry); miaoxie (A); yangfei (D); Renlipeng (OS driver)
主题: Re: 答复: 答复: [PATCH] ext4: e2fsprogs: fix inode bitmap num not integer,incompatible for ancient android devices

On Thu, Jun 28, 2018 at 07:56:59AM +0000, Gaoming (ming, consumer BG) wrote:
> You see, Inodes per group is 1708,which is illegal as you said.
>
> So, the problem exists a long time until Jun 21th 2018.
>
> You complained the problem in 2011, they do not fix it till 2018.
> Just as
> I complained, fix it, and you do not accept it. ^_^

Here's the commit. (Note the date.) Do you see it in your repository?

Or are you using an unusual inode size? (e.g., not 256 bytes, or 16
inodes per block).


- Ted

commit 06c35f935a7adadceb9ee326b3231f952f6ad203
Merge: 480a3b1 96cc54a
Author: Colin Cross <ccross@xxxxxxxxxxx>
Date: Sat Apr 30 19:08:09 2011 -0700

Merge "Make inodes per group a multiple of inodes per block"

diff --cc ext4_utils/make_ext4fs.c
index c9fd992,e37d617..22c9424
--- a/ext4_utils/make_ext4fs.c
+++ b/ext4_utils/make_ext4fs.c
@@@ -214,26 -215,10 +214,27 @@@ static u32 compute_inodes_per_group(
{
u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
- return DIV_ROUND_UP(info.inodes, block_groups);
+ u32 inodes = DIV_ROUND_UP(info.inodes, block_groups);
+ return ALIGN(inodes, (info.block_size / info.inode_size));
}

+static u32 compute_bg_desc_reserve_blocks()
+{
+ u32 blocks = DIV_ROUND_UP(info.len, info.block_size);
+ u32 block_groups = DIV_ROUND_UP(blocks, info.blocks_per_group);
+ u32 bg_desc_blocks = DIV_ROUND_UP(block_groups * sizeof(struct ext2_group_desc),
+ info.block_size);
+
+ u32 bg_desc_reserve_blocks =
+ DIV_ROUND_UP(block_groups * 1024 * sizeof(struct ext2_group_desc),
+ info.block_size) - bg_desc_blocks;
+
+ if (bg_desc_reserve_blocks > info.block_size / sizeof(u32))
+ bg_desc_reserve_blocks = info.block_size / sizeof(u32);
+
+ return bg_desc_reserve_blocks;
+}
+
void reset_ext4fs_info() {
// Reset all the global data structures used by make_ext4fs so it
// can be called again.